Astm c 321 00 (2012)

Designation C321 − 00 (Reapproved 2012) Standard Test Method for Bond Strength of Chemical Resistant Mortars1 This standard is issued under the fixed designation C321; the number immediately following[.]

Designation: C321−00 (Reapproved 2012)

Standard Test Method for

Bond Strength of Chemical-Resistant Mortars1

This standard is issued under the fixed designation C321; the number immediately following the designation indicates the year of

original adoption or, in the case of revision, the year of last revision A number in parentheses indicates the year of last reapproval A

superscript epsilon (´) indicates an editorial change since the last revision or reapproval.

This standard has been approved for use by agencies of the U.S Department of Defense.

1 Scope

1.1 This test method covers the determination of the bond

strength between resistant mortars and

chemical-resistant brick

1.2 The values stated in inch-pound units are to be regarded

as standard The values given in parentheses are mathematical

conversions to SI units that are provided for information only

and are not considered standard

1.3 This standard does not purport to address all of the

safety problems, if any, associated with its use It is the

responsibility of the user of this standard to establish

appro-priate safety and health practices and determine the

applica-bility of regulatory limitations prior to use.

2 Referenced Documents

2.1 ASTM Standards:2

C279Specification for Chemical-Resistant Masonry Units

C287Specification for Chemical-Resistant Sulfur Mortar

C904Terminology Relating to Chemical-Resistant

Nonme-tallic Materials

E4Practices for Force Verification of Testing Machines

3 Terminology

3.1 Definitions—For definitions of terms used in this test

method, see TerminologyC904

4 Significance and Use

4.1 This test offers a method of determining the bond

strength between resistant mortars and

chemical-resistant brick The results obtained by this test method should

be used as a guide in, but not as the sole basis for, selection of

a chemical-resistant material for a particular application If

failure is within the brick, then the result reported shall be stated as a minimum bond strength and it shall be noted that the brick broke

5 Apparatus

5.1 Equipment, capable of weighing materials or specimens

to 60.3 % accuracy

5.2 Equipment for Mixing Materials , consisting of a

con-tainer of suitable size, preferably made of corrosion-resistant metal, or a porcelain enameled pan, and a strong, sturdy spatula

or trowel

5.3 Equipment for Melting Sulfur , consisting of a container

of suitable size, preferably made of corrosion-resistant metal, and a heater for melting the sulfur mortar Also required is a laboratory mixer capable of operating at a speed sufficient to lift the aggregate but without beating air into the melt

5.4 Testing Machine, of the universal type, in which the load

is applied hydraulically, mechanically, or electromechanically

at a constant but adjustable rate of crosshead movement The machine shall conform to Practices E4

5.5 Guide for Marking Brick, of the type shown inFig 1

5.6 Special Test Fixture, consisting of two units of the type

shown inFig 2

5.7 Apparatus for Preparation of Mortar Joint by Casting,

of the type shown in Fig 3

5.8 Brick, as defined in1.1 See SpecificationC279

6 Temperature

6.1 The standard temperature of the laboratory equipment and materials shall be 73 6 4°F (23 6 2°C)

7 Number of Specimens

7.1 A minimum of six crossed-brick test specimens shall be prepared

8 Preparation of Crossed-Brick Test Specimens

8.1 With mortars designed for a trowel-type application, apply the mortar over the area on the brick that is marked for the joint The amount of mortar applied shall be 25 to 50 % in excess of the required amount to ensure a full joint Place one

1 This test method is under the jurisdiction of ASTM Committee C03 on

Chemical-Resistant Nonmetallic Materials and is the direct responsibility of

Subcommittee C03.01 on Mortars and Carbon Brick.

Current edition approved Aug 1, 2012 Published September 2012 Originally

approved in 1954 Last previous edition approved in 2005 as C321 – 00 (2005).

DOI: 10.1520/C0321-00R12.

2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or

contact ASTM Customer Service at service@astm.org For Annual Book of ASTM

Standards volume information, refer to the standard’s Document Summary page on

the ASTM website.

Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959 United States

of the brick, mortared side up, on a flat level surface Then

place two blocks on each side of the joint area of the bottom

brick The height of the blocks must be uniform and is dependent on the thickness of the mortar joint desired and the

FIG 1 Guide for Marking Brick

FIG 2 Special Test Fixture C321 − 00 (2012)

height of the brick; for example, if a1⁄8-in (3.2-mm) thick joint

is desired and the height of the brick laying flat is 33⁄8in (85.7

mm), then the blocks should be 31⁄2in (88.9 mm) in height in

order to provide the desired joint thickness It is suggested that

the blocks be made of wood or rigid plastic Mortar shall be

trowelled onto the marked area of the second brick The

amount of mortar applied shall be 10 to 25 % in excess of the

required amount to ensure a full joint Place the second brick

on top of the bottom brick as shown inFig 3 Compress the top

brick until its ends are firmly against the side blocks At the

same time, align the two brick-mortar contacts as parallel

surfaces Strike off the excess mortar that has been squeezed

from all sides of the joint Remove the blocks, taking care not

to disturb the joint area Normally, with chemical-resistant

mortars, the joint thickness does not exceed 1⁄8in Allow the

mortar to set for a minimum of 24 h or longer if recommended

by the mortar manufacturer before handling the specimens

8.2 With sulfur mortars to be applied by casting, mount the

brick in a special jig as shown inFig 3 Mask any open points

to prevent leakage Prepare sulfur mortar in accordance with

Specification C287 Pour the molten mortar into the joint

cavity provided by this assembly Allow 15 min for the mortar

to set before handling the specimens

9 Conditioning Brick

9.1 Drying—Dry the test brick in a ventilated oven at 230 to

239°F (110 to 115°C) for not less than 24 h and until two

successive weighings at intervals of 2 h show an increment of

not greater than 0.2 % of the last previously determined weight

of the specimen Cool the brick to 73 6 4°F before applying

the mortar (Note 1) Mark the brick as shown in Fig 1, to

ensure that the crossed bricks will be at right angles to each

other and centered one on the other when the specimen is

assembled At the same time, mark the contact points for the

load test in the special test fixture (see12.1)

N OTE 1—Brick to be used with hydraulic cements shall not be dried.

10 Preparation of Mortar

10.1 For mortars to be applied by troweling, prepare a 1200

to 1500-g sample of mortar, mixing it in the proper proportions and in the manner specified by the manufacturer of the materials If the proportions so specified are by volume, weigh the materials and report the corresponding proportions by weight

10.2 For sulfur mortars to be applied by casting, prepare samples in accordance with 7.1.1 of Specification C287

11 Conditioning Test Specimens

11.1 Condition the specimens, except those of sulfur and hydraulic cement mortars, for seven days at 73 6 4°F (23 6 2°C) Other conditioning temperatures are acceptable, pro-vided they are reported with the test data In the case of sulfur mortars, test the samples after 48 h The conditioning time and temperature may be varied to establish time-temperature-strength relationship or to conform with intended service Store specimens made with hydraulic cement mortars for 14 days in

a moist cabinet at 73 6 4°F (23 6 2°C) and at a relative humidity of not less than 90 %

11.2 Take care in handling the specimens to avoid abuse, such as lifting the unit by the top brick, or stacking specimens one on another

12 Procedure

12.1 Mount the test specimen in the special test fixture as shown inFig 2andFig 4 Place the specimen on the support points of the bottom head in such a manner that the specimen

is balanced The marked contact points on the bottom surface

of the top brick must match the support points of the bottom test head Position the apparatus to match the contact points of the top head with the marked contact points on the top surface

of the bottom brick

FIG 3 Apparatus for Preparation of Mortar Joint by Casting

C321 − 00 (2012)

12.2 With the cross-head movement of 0.20 to 0.25 in./min

(5 to 6.4 mm/min) when the machine is running without load,

apply load until failure and record the maximum load applied

12.3 Inspect the joint after testing and note whether the

failure was in the mortar, between the mortar and the brick, or

in the brick, and the relative areas involved This will indicate

which is the greater, cohesion within the mortar or adhesion

between the mortar and brick or within the brick

13 Calculation

13.1 Calculate the bond strength as follows:

A 5 L/J

where:

A = bond strength, psi (or MPa),

L = maximum load applied, lbf (or N), and

J = area of joint, in.2(or mm2)

14 Report

14.1 The report shall include the following:

14.1.1 Identification of mortar tested and the proportions of the mortar by weight,

14.1.2 Identification of brick used, including brand, type, and surface,

14.1.3 Age of specimen at time of test, 14.1.4 Average bond strength,

14.1.5 Standard deviation, 14.1.6 Number of specimens tested, 14.1.7 Any variation from the standard procedure, and 14.1.8 Type of failure, that is, cohesive, adhesive, or failure

of the brick

15 Precision and Bias

15.1 Precision and bias for this test method have not been established

15.2 Test specimens that are manifestly faulty should be rejected and not considered in determining the bond strength of the mortar

15.3 If any bond strength value differs from the mean by more than 15 %, the farthest value from the mean shall be rejected and the mean recalculated If any value still differs from the new mean by more than 15 %, the farthest value shall again be rejected and the mean recalculated If any value remains 15 % from the mean, the test shall be rerun

15.4 If less than four values remain, the test shall be rerun

16 Keywords

16.1 adhesion; bond; bond strength; brick; chemical-resistant brick; chemical-chemical-resistant mortar; cohesion; mortar

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FIG 4 Cross-Brick Specimen Mounted on Special Fixture

C321 − 00 (2012)